Molecular structure and mild steel/HCl corrosion inhibition of 4,5-Dicyanoimidazole: Vibrational, electrochemical and quantum mechanical calculations

Ahmed M. Abuelela, Mahmoud A. Bedair, Wajdi M. Zoghaib, Lee D. Wilson, Tarek A. Mohamed*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Raman (3500-50 cm−1) and FT-ATR/FT-infrared (3500-500/4000-200 cm−1) spectrum of 4,5-Dicyanoimidazole (DCI) were recorded and analyzed by normal coordinate analysis calculations. In addition, we have studied the molecular structure of DCI by means of B3LYP Density Functional Theory (DFT) using 6-31g(d) basis set. Aided by computational outcomes, all vibrational bands were assigned quantitatively to their corresponding fundamentals. The corrosion inhibition efficiency of DCI towards mild steel in 1.0 M HCl has been investigated experimentally and theoretically. Electrochemical impedance spectroscopy, electrochemical frequency modulation and polarization measurements along with thermodynamic predictions were assigned to both the anodic and cathodic inhibition. DCI-metal interactions and charge reallocation were analyzed in terms of Frontier molecular orbital (FMO) and Natural bond orbital (NBO) analysis. Global reactivity descriptors; ionization potential (IP), electron affinity (A), electronegativity (χ), chemical potential (µ), chemical hardness (η), and electrophilicity index have been calculated and assigned to the inhibition efficiency. Good correlation between the theoretical calculations and experimental measurments has been achieved. The results are compared with similar molecular systems whenever appropriate.

Original languageEnglish
Article number129647
JournalJournal of Molecular Structure
Publication statusPublished - Apr 15 2021
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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